Can I still use fly mode in 2.7?
If you want to use both fly and walk mode without toggling settings in your preferences constantly, it's still accessible in 3D view > Header > View > Navigation > Fly mode:



Since that's kind of a pain to get to if you use it a lot, you can:


Use the search menu (Space > fly)
Create a custom shortcut by right clicking on the option in the menu and selecting Add Shortcut.


This way you can have both fly and walk mode within easy access.